Alex Chia-Chun Hsu

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The MAC protocol of a cognitive radio (CR) device should allow it to access unused or under-utilized spectrum without (or with minimal) interference to primary users dynamically. To fulfill such a goal, we propose a cognitive MAC protocol using statistical channel allocation and call it SCA-MAC in this work. SCA-MAC is a CSMA/CA-based protocol, which(More)
Machine-Type-Communications (MTC) applications are automated applications, which involve communications between machines or devices without human intervention. Such applications are widely adopted in our everyday life [1]. Though cellular mobile networks could offer MTC ubiquitous network access service with widely deployed infrastructure, they were(More)
In this paper, we present an enhanced adaptive frequency hopping (EAFH) mechanism for improving the performance of frequency hopping-based wireless personal area networks (WPANs) under frequency-static and frequency-dynamic interference. The proposed mechanism monitors the overall packet error rate (PER) of the system to determine the right number of(More)
A non-collaborative coexistence mechanism for wirelessfidelity (Wi-Fi) and bluetooth (BT) systems based on dynamic packet fragmentation is proposed in this work. The basic idea is to adapt the packet length of Wi-Fi in the MAC layer such that the fragmented packet has a better chance to survive the interference from the nearby BT devices. We first develop(More)
Skeletal muscle contraction and glycogenolysis are closely coupled. The standard explanation for this coupling, as taught in modern biochemistry textbooks, is that the metabolic products of contraction (ADP, AMP, P(i)) feed back to activate glycogenolytic enzymes, thus providing for resynthesis of ATP. However, both in vivo (31)P MRS analyses and chemical(More)
The appearance of new peaks in the 7.7-8.6 and 6.8-7.4 ppm regions of the postexercise (1)H spectrum of frog muscle is reported. These new peaks result from the splitting of single pre-exercise carnosine C-2 and C-4 peaks into two peaks, representing the intracellular pH (pH(I)) of oxidative and glycolytic fibers. The following data support this conclusion:(More)
Featuring massive number of devices, Machine Type Communications (MTC) poses great challenges for radio access network (RAN) with its overloading problem that has been aggressively addressed by 3GPP as an essential working item. In this article, we first introduce random access procedure in LTE-A. Then we address the issue of RACH overload coming from(More)
As the end product of anaerobic metabolism and a source of H(+), lactic acid is important in metabolism and pH regulation. Several methods have been introduced to calculate changes in the lactate anion (Lac(-)) concentration in exercising skeletal muscle from information derived from the (31)P spectrum. Alternatively, Lac-may be observed directly with (1)H(More)
Dynamic spectrum access (DSA) technique enables dynamic access of unused or under-utilized spectrum without causing interference to existing incumbent service. Through DSA, a DSA device (second user) is offered opportunities to monitor a swath of spectrum, which is divided into myriad channels, in the licensed band. A great number of available channels(More)
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